Modern electronic anti-theft systems comprise an access authorization system, for example, a central locking system, a driver authorization system, for example with an immobilizer and an alarm system. These types of anti-theft systems are disclosed in German Patents DE 199 24 081 A1 and DE 197 56 341 A1.
A modern access authorization system for a motor vehicle comprises an electronic lock in a locking system, which communicates with the electronic key with which it is associated. This lock typically communicates with a control device associated with it, for example the control device of the engine controller, an immobilizer, an alarm system or similar. In this way, after positive verification of coded data from an operator, or a data carrier carried by said person with coded data stored in the motor vehicle, the access authorization system can be overridden. For this purpose, the key inserted into a recess of the lock immediately exchanges coded data with the lock in stand-by mode, and after positive evaluation, the corresponding lock in the access authorization system is released. At the same time as the access authorization system is released, the corresponding door locks are unlocked and the immobilizer and the alarm system are deactivated. The operator is then able to open the door and operate the motor vehicle.
Modern access authorization systems for motor vehicles additionally or alternatively enable keyless access to the motor vehicle. Such a type of system is for example, the Passive Access Start and Entry system (PASE) developed by Siemens VDO Automotive. For example, an access authorization request can be initiated by activating a door handle. This is also referred to as a passive access request.